FWIW, I have used DX lights with protected cells for 2 years with no scares.

FWIW, I have used DX lights with protected cells for 2 years with no scares

And therein lies your answer…

I’ve been using li-ion since about 2004, with protective circuits, surprisingly without a problem.

It’s when people build a pack without the neccessary protective circuits that problems occur, this seemed to be occuring back in the day when I started. Nice cheap cells from china strapped together without the protection is a recipe for disaster.

Li-Ion are fine as long as you keep them dry, when the cells get wet they expand and the contents seep out – not nice.

Li-Po are the ones i have heard all the scare stories about, is it thes ones you mean?

Rusty, LI-Ion and LiPo. I work in the industry and Li-Ion were used in very specialist situations about 15 years ago. In those days, Li content was much larger and they were considered really dangerous. Both have the potential to be dangerous (hence the protection circuits). Also there are still very strict limits on how much you can air freight in a given volume and IATA is deeply concerned at the qty of Li being transported by air from China (see IATA Link)

With billions of LiPo and Li-Ion batteries now in play, I wonder if the danger has only ever been theoretical…

Ref: How Stuff Works

Why is there a chance for explosion? Li-ion batteries work by separating its positive and negative sides by a thin layer, called an electrolyte. The electrolyte is perforated to allow the lithium ions to pass through from one side of the chamber to the other, thus generating a current. Tiny bits of metal that result from the manufacturing process can potentially get stuck in those perforations, preventing the ions from freely flowing. Pressure and heat can then build up, causing an explosion. Also, allowing the ions to move too quickly can lead to overheating as well.

Personally I am more worried about a ELE event than being injured by my lights, or maybe not…

When I first read about li-ion and the dangers, it seemed to be when an unprotected cell was shorted, probably leading to this:

Also, allowing the ions to move too quickly can lead to overheating as well

and maybe then onto fire\explosion..?

Bellerophon. Correct: As the batteries are sealed, anything that leads to a build up of internal pressure can lead to failure of the casing (sometimes explosively). Examples are: overcharging, charging to fast, discharging too fast. Normally manufactures add protection (vents, fuses etc.) but not always. when lithium makes contact with air, it spontaneously combusts. This is why airlines regulate by virtue of lithium content / concentration. The “how it works” explanation seems bizare.

Kona: a few years ago, Sony was sufficiently worried by the potential for their laptop batteries to explode that they withdrew them on a massive scale at a cost of millions of dollars. I have not heard of any corporate business investing at such levels to avoid an ELE. Perhaps you should have a word with them?

From 24 yrs in the battery industry and just over 13 in Li-Ion & Li-Po assembly and design.

Li-Ion & Li-Po cells are perfectly safe so long as they are looked after & used within the limits of the specification in which they were built for.
It is when they are abused and used out of this limit that problems occur, ie circuits taken off or built from old cells from laptops etc

The Protection circuit protects against: Over-Charge, Under-Discharge, short circuit protection & Over current protection. Added to this each Li-Ion cell will additionally have its on resetable fuse inbuilt under the positive cap. There may also be a non-resettable fuse & Thermal fuse depending on application.

The protection circuit on these type of batteries are designed only as a back up should the equipment in which they are designed is faulty or fail and should NOT alone be used to control the batteries use. The equipment set to switch off within the cut off voltage and charger set to cut off at the end of charge voltage.

The Protection circuit also monitors each series cell within the battery and should one cell fail or become inbalanced (different voltage to the rest of the cells) the protection circuit will stop the battery from working – again without the circuit the other cells would try to charge the rogue cell (not nice to happen!)

There is too much dodgy stuff out there that is poorly built and not UL approved. This can cost around >£8k to get tested and approved, so you imagine this for every diferent type of battery built. You can get round it by classing them as samples or similar design. Lots of ground that even FIA keep changing.

There are too many dodgy ebay shops out there selling at ridiculous prices and most of the batteries come from Shenzhen, but if you dont know the manufacturer they could be made from anything and classed as anything. I have seen loads of supposed 2.6Ah cells and when tested are lucky to be 2Ah. Same with the 3Ah cells which struggle to meet anywhere near to the spec.

As an extra bit, im off to visit my supplier in a few months time. They have invited me over to see them first hand to discuss new target markets and a guided tour of their factory is also laid on.

Good info Smudge, Thx. I worked with power source design about 15-20 years ago. In those days our military users would only take NiMH rechargeables, with single use Lithium for arctic conditions. This because Lithium rechargeables were considered too dangerous from the handling point of view. (Ironic when you consider what else they handle!). The biggest concern was spontaneous combustion of a damaged battery. I’m assuming that today’s commercial batteries won’t do this if opened. Is that correct?

Plus you have the temperature to put up with. The military batteries we used to build went down to -50C.

The French cells we used as part of the UL test was to drive a nail through the cell and made sure it didn’t explode or ignite.

Did you used to use the Electrochem cells for the Artic conditions? These are also widely used in the oil industry for the high temperatures as well – again single use.